Many devices and methods for treating obesity have been made and used, including but not limited to adjustable gastric bands. An example of such an adjustable gastric band is disclosed in U.S. Pat. No. 6,067,991, entitled “Mechanical Food Intake Restriction Device,” which issued on May 30, 2000, and which is incorporated herein by reference. To the extent that an adjustable gastric band system is fluid based, those of ordinary skill in the art will appreciate that it may be advantageous to acquire data indicating the pressure of fluid in the band system. Similar advantages may be achieved with fluid-filled members implanted within the stomach cavity or elsewhere. Such pressure data may be obtained before, during, and/or after pressure adjustment, and may be useful for adjustment, diagnostic, monitoring, or other purposes. The foregoing examples are merely illustrative and not exhaustive. While a variety of techniques and devices have been used treat obesity, it is believed that no one prior to the inventors has previously made or used an invention as described in the appended claims.